Former garda press officer Supt Dave Taylor claims to have given negative briefings about Sgt McCabe to a number of reporters, on the orders of then commissioner Martin Callinan.

He says he was ordered to tell them that the whistleblower - who exposed the force's penalty points scandal - had been at the centre of a child sexual assault investigation.

However, the tribunal was told that five of the nine journalists listed by Supt Taylor denied being briefed in this way.

The other four cited journalistic privilege and have not corroborated Supt Taylor's claims.

Random

The five who deny being briefed are Paul Williams of the Irish Independent and Newstalk, Paul Reynolds and John Burke of RTE, Juno McEnroe of the Irish Examiner and Michael O'Toole of the Irish Daily Star.

Mr O'Toole said he wanted to claim journalistic privilege, but no senior garda had ever smeared Sgt McCabe to him.

The journalists who cited privilege are Conor Lally of the Irish Times, John Mooney of the Sunday Times and Cormac O'Keeffe and Daniel McConnell of the Irish Examiner.

Under questioning from tribunal counsel Diarmaid McGuinness, Supt Taylor was unable to say where and when he briefed journalists about Sgt McCabe.

Some briefings would have taken place on the phone while others would have been on the margins of press conferences.

Former commissioner Martin Callinan

Tribunal chairman Mr Justice Peter Charleton asked if he could give details of the specific reaction of any journalist, but Supt Taylor said the journalists "just took the information".

He said the briefings began after he was given an order by Mr Callinan in mid-2013 and ended in March 2014 when the commissioner resigned.

At the time he did not believe what he was doing was wrong, but subsequently realised it was.

Supt Taylor said Mr Callinan was "deeply frustrated" that the penalty points issue was not dying down.

He said he discussed the order with then deputy commissioner Noirin O'Sullivan and also told garda communications director Andrew McLindon.

Ms O'Sullivan and Mr Callinan have denied any knowledge of or involvement in a smear campaign, while Mr McLindon says he was never told by Supt Taylor of any order to brief negatively against Sgt McCabe.

Supt Dave Taylor

The tribunal heard there was a conflict between the evidence of Supt Taylor and that of Paul Williams, who in 2014 published an interview with the young woman who had alleged Sgt McCabe sexually assaulted her as a child.

Sgt McCabe had been cleared of the allegation in 2007.

Mr Williams has said he contacted Supt Taylor about a week after meeting the woman with a number of questions.

However, Supt Taylor said he thought Mr Williams contacted him on the day of the interview, not with questions but to let him know it had taken place.

Agitated

Earlier, the tribunal heard how Mr Callinan was annoyed when an article appeared in the Irish Independent in April 2013 saying the commissioner had penalty points quashed.

The journalist who wrote the article said she called to the commissioner's house to check that the Martin Callinan living at that address was him.

Mr Callinan was "agitated" and felt it was a breach of his privacy, Supt Taylor said.

He added that a few days later, he passed on this "annoyance and concern" at a meeting with a newspaper executive.